Routing Wiring Segmentation for Flexible OLED Bending Stress

Solution Overview

Problem

Flexible organic light emitting display apparatuses face cracks in the routing wiring during increased bending, leading to short circuits and potential water or moisture permeation, which compromises the integrity of the device.

Innovation Solution

The organic light emitting display apparatus incorporates a substrate with a display area and a bending area, featuring a pixel array layer, a thin film transistor, a planarization layer, a light emitting device layer, routing wiring, and an encapsulation layer. The routing wiring is connected to the driving wiring through a contact hole, and the planarization layer, made of organic material, reduces stress and facilitates easy bending while the encapsulation layer protects against external moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the degree of bending is increased to reduce bezel size, then the bezel size is reduced, but a crack occurs in the routing wiring causing a short circuit

Engineering Contradiction:

Improvebezel sizeVSAvoidrouting wiring integrity

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The routing wiring is divided into multiple segments with different bending radii. The first routing wiring has a first bending radius while the second routing wiring has a second bending radius different from the first, allowing each segment to accommodate bending stress differently and prevent crack propagation throughout the entire wiring structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the routing wiring are designed with different structural properties. Specifically, the routing wiring includes segments with different bending radii tailored to their local stress requirements, with the neutral axis positioned within the thickness of the wiring to optimize local stress distribution and prevent cracking in high-stress bending areas.

Inventive Principle:

Principle #3Local quality

2Area of stationary object

If the degree of bending is increased to reduce bezel size, then the bezel size is reduced, but water or moisture permeation occurs through the crack

Engineering Contradiction:

Improvebezel sizeVSAvoidwater or moisture permeation

Core Design Contradiction:

Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The routing wiring is divided into multiple segments with different bending radii. The first routing wiring has a first bending radius while the second routing wiring has a second bending radius different from the first, allowing each segment to accommodate bending stress differently and prevent crack propagation throughout the entire wiring structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the routing wiring are designed with different structural properties. Specifically, the routing wiring includes segments with different bending radii tailored to their local stress requirements, with the neutral axis positioned within the thickness of the wiring to optimize local stress distribution and prevent cracking in high-stress bending areas.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If flexible material is used to enable bending, then the device becomes flexible and easy to carry, but cracks occur in the routing wiring during bending

Engineering Contradiction:

ImproveflexibilityVSAvoidrouting wiring integrity

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The routing wiring is divided into multiple segments with different bending radii. The first routing wiring has a first bending radius while the second routing wiring has a second bending radius different from the first, allowing each segment to accommodate bending stress differently and prevent crack propagation throughout the entire wiring structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different portions of the routing wiring are designed with different structural properties. Specifically, the routing wiring includes segments with different bending radii tailored to their local stress requirements, with the neutral axis positioned within the thickness of the wiring to optimize local stress distribution and prevent cracking in high-stress bending areas.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS11063101B2Organic light emitting display apparatus

Publication Date: 2021.07.13 LG DISPLAY CO LTD

AI summary

An organic light emitting display apparatus can include a substrate including a display area and a bending area; a pixel array layer including a driving wiring in the display area, and a thin film transistor electrically connected to the driving wiring; a planarization layer covering the pixel array layer; a light emitting device layer disposed on the planarization layer, the light emitting device layer being electrically connected to the thin film transistor; a routing wiring disposed in the bending area, the routing wiring being electrically connected to the driving wiring; a wiring contact part including a contact hole for electrically connecting the driving wiring to the routing wiring; and an encapsulation layer covering the light emitting device layer and the wiring contact part.